Thienopyrimidine derivatives and production methods thereof

ABSTRACT

The present invention provides a production method of a thienopyrimidine derivative or a salt thereof which has a gonadotropin releasing hormone (GnRH) antagonistic action with high quality in high yield. The present invention provides a method of producing a thienopyrimidine derivative, which comprises reacting 6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione or salt thereof, 1,1′-carbonyldiimidazole or a salt thereof and methoxyamine or a salt thereof, and the like.

TECHNICAL FIELD

The present invention relates to a production method of athienopyrimidine derivative having a gonadotropin releasing hormone(GnRH) antagonistic action.

BACKGROUND OF THE INVENTION

Secretion of anterior pituitary hormones undergoes feedback control byperipheral hormones secreted from target organs of the respectivehormones and by secretion-regulating hormones from the hypothalamus,which is the upper central organ of the anterior lobe of the pituitary(hereinafter, these hormones are collectively called “hypothalamichormones” in this specification). Presently, as hypothalamic hormones,the existence of nine kinds of hormones including, for example,thyrotropin releasing hormone (TRH), and gonadotropin releasing hormone[GnRH, sometimes called as LH-RH (luteinizing hormone releasinghormone)] has been confirmed. By preventing LH-RH from binding with theLH-RH receptor in the anterior pituitary gland and suppressing thesecretion of luteinizing hormone (LH) and follicle stimulation hormone(FSE) from the anterior pituitary gland, an antagonist for gonadotropinreleasing hormone controls the effect of LH and FSH on the ovary,reduces the level of estrogen in blood, which is known to be associatedwith the development of endometriosis and uterine fibroids, and isexpected to improve the symptoms of these disorders.

As thienopyrimidine derivatives having gonadotropin releasing hormoneand production methods thereof, for example, those described in PatentDocument 1 and 2 and Non-Patent Document 1 are known.

DOCUMENT LIST Patent Document

-   Patent Document 1: WO 00/56739-   Patent Document 2: WO 2004/067535

Non-Patent Document

-   Non-Patent Document 1: J. Med. Chem., 2011, vol. 54, pages 4998-5012

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

There is a demand for the development of a safe production method of athienopyrimidine derivative or a salt thereof which has a gonadotropinreleasing hormone antagonistic action with high quality (e.g., highpurity) in high yield.

Means of Solving the Problems

The present inventors have conducted intensive studies in an attempt tosolve the above-mentioned problem and found that, by employing theproduction method of the present invention,1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with high quality can be more safely obtained in highyield, which resulted in the completion of the present invention.

Accordingly, the present invention relates to

[1] a method of producing1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof, which comprises reacting6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor salt thereof, 1,1′-carbonyldiimidazole or a salt thereof andmethoxyamine or a salt thereof;[2] the method of the above-mentioned [1], wherein the1,1′-carbonyldiimidazole or a salt thereof is used in an amount of 1.6to 2.5 equivalents relative to6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof, and the methoxyamine or a salt thereof is used in anamount of 1.0 to 1.5 equivalents relative to 1,1′-carbonyldiimidazole ora salt thereof;[2A] a method of producing a crystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof, which comprises reacting6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor salt thereof, 1,1′-carbonyldiimidazole or a salt thereof andmethoxyamine or a salt thereof, and adding tetrahydrofuran to theresulting reaction mixture (may be a reaction solution) or1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof isolated from the resulting reaction mixture (may be areaction solution);[3] a method of producing a crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof, which comprises recrystallizing a crystal of atetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof using an alkyl alcohol and one solvent selected fromthe group consisting of dimethylsulfoxide, dimethylformamide(N,N′-dimethylformamide, in the present specification, to also bereferred to as DWF) and dimethylacetamide (N,N′-dimethylacetamide, inthe present specification, to also be referred to as DMAc);[4] a method of producing ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamateor a salt thereof, which comprises reacting2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid or a salt thereof with 3-amino-6-methoxypyridazine or a saltthereof in the presence of propylphosphonic anhydride and a base;[5] a method of producing1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof, which comprisesreacting2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid or a salt thereof with 3-amino-6-methoxypyridazine or a saltthereof in the presence of propylphosphonic anhydride and a base,subjecting the obtained ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-S-(4-nitrophenyl)thiophen-2-yl]carbamateor a salt thereof to a cyclization reaction,subjecting the obtained1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof to a reduction reaction, andreacting the obtained6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof, 1,1′-carbonyldiimidazole or a salt thereof andmethoxyamine or a salt thereof;[6] a method of producing ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof, which comprises reacting ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof with N-bromosuccinimide in the presence of2,2′-azobis(2,4-dimethylvaleronitrile) and trifluoromethylbenzene;[7] a method of producing1-{4-[1-(2,6-difluorobenzyl)-5-dimethylamninomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof, which comprisesreacting ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof with N-bromosuccinimide in the presence of2,2′-azobis(2,4-dimethylvaleronitrile) and trifluoromethylbenzene,reacting the obtained ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof with dimethylamine or a salt thereof,subjecting the obtained ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylateto hydrolysis,reacting the obtained2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid or a salt thereof with 3-amino-6-methoxypyridazine or a saltthereof in the presence of propylphosphonic anhydride and a base,subjecting the obtained ethyl(2,6-difluorobenzyl)-[4-dimethylamninomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamateor a salt thereof to a cyclization reaction,subjecting the obtained1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof to a reduction reaction, andreacting the obtained6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof, 1,1′-carbonyldiimidazole or a salt thereof andmethoxyamine or a salt thereof;[8] a compound represented by the formula (I):

wherein R¹ is a hydroxy group, a C₁₋₆ alkoxy group or a C₁₋₆alkoxy-pyridazinylamino group,or a salt thereof (in the present specification, to also be referred toas compound (I));[9] a compound represented by the formula (II):

wherein R² is a nitro group or an amino group, or a salt thereof (in thepresent specification, to also be referred to as compound (II)).

Effect of the Invention

According to the present invention,1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with high quality can be more safely produced in highyield. In addition, a crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with high quality can be easily and efficientlyproduced.

Compounds (I) and (II) are useful as raw material compounds forproducing1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a powder X-ray diffraction pattern of a crystal of atetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea.

FIG. 2 shows a powder X-ray diffraction pattern of a crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea.

DETAILED DESCRIPTION OF THE INVENTION

The definitions of the terms used in the present invention are explainedin detail in the following.

In the present specification, “C₁₋₆ alkoxy (group)” means, for example,methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy,tert-butoxy, pentyloxy, isopentyloxy, hexyloxy or the like. The C₁₋₆alkoxy group for R¹ is preferably ethoxy.

The “C₁₋₆ alkoxy-pyridazinylamino group” for R¹ means a pyridazinylaminogroup substituted by 1 to 3 (preferably 1) C₁₋₆ alkoxy group(s). The“C₁₋₆ alkoxy-pyridazinylamino group” for R¹ is preferably a 6-C₁₋₆alkoxy-3-pyridazinylamino group, particularly preferably a6-methoxy-3-pyridazinylamino group.

The“1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea”in the present specification is identical toN-(4-(1-(2,6-difluorobenzyl)-5-((dimethylamino)methyl)-3-(6-methoxy-3-pyridazinyl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl)phenyl)-N′-methoxyureadescribed in Patent Document 2.

Next, the production method of the present invention is explained.

Hereinafter, the “room temperature” generally means 1-30° C.

In the following reaction, the raw material compounds, productionintermediates and objective compounds may be in the form of a salt.Examples of such salt and salts of compound (I) and compound (II)include a salt with an inorganic acid, a salt with an organic acid, anda salt with an acidic amino acid. Preferable examples of the salt withan inorganic acid include a salt with hydrochloric acid, hydrobromicacid, nitric acid, sulfuric acid or phosphoric acid. Preferable examplesof the salt with an organic acid include a salt with formic acid, aceticacid, trifluoroacetic acid, phthalic acid, fumaric acid, oxalic acid,tartaric acid, maleic acid, citric acid, succinic acid, malic acid,methanesulfonic acid, benzenesulfonic acid or p-toluenesulfonic acid.Preferable examples of the salt with an acidic amino acid include a saltwith asparagine acid or glutamic acid. Among them, pharmaceuticallyacceptable salts are preferably.

The obtained compound in each step can be used directly for the nextreaction as the reaction mixture or as a crude product, ox can also beisolated according to a conventional method from the reaction mixture,and can also be easily purified according to a separation means (e.g.,recrystallization, distillation, chromatography etc.). When the compoundin the reaction scheme is a commercially available product, it can alsobe used directly.

(Step 1)

Ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof (hereinafter to also be referred to as BNTC) can beproduced by reacting ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof (hereinafter to also be referred to as FNTC) withN-bromosuccinimide in the presence of2,2′-azobis(2,4-dimethylvaleronitrile) and trifluoromethylbenzene. Thisreaction can also be carried out in a solvent.

The amount of the N-bromosuccinimide to be used is generally 1.0-1.5equivalents, preferably 1.1-1.4 equivalents, more preferably 1.2-1.3equivalents, relative to FNTC.

The amount of the 2,2′-azobis(2,4-dimethylvaleronitrile) to be used isgenerally 0.01-0.2 equivalents, preferably 0.05-0.15 equivalents,relative to FNTC.

The amount of the trifluoromethylbenzene to be used is generally 0.1-1.0mL, preferably 0.2-0.6 mL, per 1 mmol of FNTC.

The solvent is not particularly limited as long as the reactionproceeds. Examples thereof include ethyl acetate, carbon tetrachloride,dichloromethane, dichloroethane, chlorobenzene, acetonitrile and thelike. The solvent is preferably ethyl acetate. In addition,trifluoromethylbenzene or a mixed solvent of trifluoromethylbenzene andan ester (e.g., ethyl acetate etc.) can also be used as a solvent. Inthe case of the mixed solvent, the ratio (volume ratio) oftrifluoromethylbenzene:an ester (e.g., ethyl acetate etc.) in the mixedsolvent is preferably 1:0-1:50, more preferably 1:3-1:30.

The reaction temperature is generally 50-80° C., preferably 60-80° C.,more preferably 65-75° C.

The reaction time is generally 0.1-5 hr, preferably 0.5-1 hr.

In this step, by using, as a radical initiator,2,2′-azobis(2,4-dimethylvaleronitrile) having lower toxicity than2,2′-azobisisobutyronitrile, the bromination reaction can be safelycarried out as compared with the reaction described in Patent Document 1or Non-Patent Document 1. In addition, by using, as a solvent,trifluoromethylbenzene and an ester (e.g., ethyl acetate etc.) havinglower toxicity, the bromination reaction can be rapidly carried out ascompared with the reaction described in Patent Document 1 or Non-PatentDocument 1, and therefore, the production of the impurities can besuppressed.

In another embodiment, the reaction can also be carried out in theabsence of trifluoromethylbenzene. Even when carried out in the absenceof trifluoromethylbenzene, and BNTC can be produced as according to themethod described above or a method analogous thereto.

FNTC can be produced according to the method described in PatentDocument 1 or a method analogous thereto.

(Step 2)

Ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylateor a salt thereof (hereinafter to also be referred to as ANTC) can beproduced by reacting BNTC with dimethylamine or a salt thereof. Thisreaction can also be carried out in a solvent. ANTC is compound (I)wherein R¹ is ethoxy.

The amount of the dimethylamine or a salt thereof (preferablydimethylamine hydrochloride) to be used is generally 1.0-3.0equivalents, preferably 1.2-1.8 equivalents, relative to BNTC.

A base may be used for preferred progress of the reaction. Examples ofthe base include triethylamine, diisopropylethylamine and the like. Theamount of the base to be used is generally 1.0-5.0 equivalents,preferably 2.0-3.0 equivalents, relative to BNTC.

The solvent is not particularly limited as long as the reactionproceeds. Examples thereof include dimethylformamide (DMF),dimethylacetamide (DMAc), tetrahydrofuran and the like. The solvent ispreferably DMF. The amount of the solvent to be used is generally 0.5-10mL, preferably 2.0-4.0 mL, per 1 mmol of BNTC.

The reaction temperature is generally 0-30° C., preferably 10-20° C.

The reaction time is generally 0.5-24 hr, preferably 1-2 hr.

Compound (I) wherein R¹ is a C₁₋₆ alkoxy group can be produced accordingto the method described in Step 2 or a method analogous thereto.

(Step 3)

2-[(2,6-Difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid or a salt thereof (hereinafter to also be referred to as NTCA) canbe produced by subjecting ANTC to hydrolysis. This reaction can also becarried out in a solvent. ANTC is compound (I) wherein R¹ is ethoxy.NTCA is compound (I) wherein R¹ is a hydroxy group.

The hydrolysis is carried out using a base. The base is not particularlylimited, and a base known per se can be used. Examples of the baseinclude potassium hydroxide, sodium hydroxide, lithium hydroxide. Amongthem, potassium hydroxide is preferable. The amount of the base to beused is generally is 1-2 equivalents, preferably 1.2-1.8 equivalents,relative to ANTC.

The hydrolysis is generally carried out in a water-soluble organicsolvent. The water-soluble organic solvent is not particularly limitedas long as the reaction proceeds. Examples thereof include ethanol,methanol, tetrahydrofuran and the like. The amount of the solvent to beused is generally 1-10 mL, preferably 4-6 mL, per 1 mmol of ANTC.

The reaction temperature is generally 0-80° C., preferably 55-65° C.

The reaction time is generally 1-24 hr, preferably 3-6 hr. Compound (I)wherein R¹ is a C₁₋₆ alkoxy group can be produced according to themethod described in Step 2 or a method analogous thereto.

(Step 4)

Ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamateor a salt thereof (hereinafter to also be referred to as NNTC) can beproduced by reacting NTCA with 3-amino-6-methoxypyridazine or a saltthereof (preferably 3-amino-6-methoxypyridazine hydrochloride) in thepresence of propylphosphonic anhydride and a base. This reaction canalso be carried out in a solvent.

NTCA is compound (I) wherein R¹ is a hydroxy group. NNTC is compound (I)wherein R¹ is a 6-methoxy-3-pyridazinylamino group.

The amount of the 3-amino-6-methoxypyridazine or a salt thereof to beused is generally 1.0-3.0 equivalents, preferably 1.1-1.5 equivalents,relative to NTCA.

The amount of the propylphosphonic anhydride to be used is generally1.0-3.0 equivalents, preferably 1.1-1.5 equivalents, relative to NTCA.

Examples of the base include diisopropylethylamine, triethylamine andthe like. The amount of the base to be used is generally 1-4equivalents, preferably 2-3 equivalents, relative to NTCA.

The solvent is not particularly limited as long as the reactionproceeds. Examples thereof include dimethylacetamide (DMAc),dimethylformamide, dimethylsulfoxide, tetrahydrofuran, acetonitrile,ethyl acetate and the like. The amount of the solvent to be used isgenerally 1-10 mL, preferably 2-4 mL, per 1 mmol of NTCA.

The reaction temperature is generally 0-80° C., preferably 50-60° C.

The reaction time is generally 1-24 hr, preferably 1-3 hr.

Compound (I) wherein R¹ is a C₁₋₆ alkoxy-pyridazinyl group can beproduced according to the method described in Step 4 or a methodanalogous thereto.

3-Amino-6-methoxypyridazine or a salt thereof (hereinafter to also bereferred to as AMP) may be used a commercially available product, or canalso be produced, for example, according to the following method.

(Step 4′)

AMP can be produced by reacting 3-amino-6-chloropyridazine (hereinafterto also be referred to as ACP) with sodium methoxide. This reaction canalso be carried out in a solvent.

The amount of the sodium methoxide to be used is generally 1.0-2.5equivalents, preferably 1.1-1.5 equivalents, relative to ACP.

The solvent is not particularly limited as long as the reactionproceeds. Examples thereof include methanol, ethanol, toluene and thelike. The amount of the solvent to be used is generally 0.1-10 mL,preferably 0.5-1 mL, per 1 mmol of ACP.

The reaction can also be carried out under high pressure. The internalpressure of the reaction container is generally 0.6-0.9 MPa, preferably0.65-0.75 MPa.

The reaction temperature is generally 110-140° C., preferably 120-135°C.

The reaction time is generally 6-24 hr, preferably 7-9 hr.

(Step 5)

1-(2,6-Difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof (hereinafter to also be referred to as NNTP) can beproduced by subjecting NNTC to a cyclization reaction. This reaction iscarried out in a solvent. NNTC is compound (I) wherein R¹ is a6-methoxy-3-pyridazinylamino group. NNTP is compound (II) wherein R² isa nitro group.

The cyclization reaction can be carried out in the presence of a base.The base is not particularly limited, and a base known per se can beused. Examples thereof include sodium methoxide, sodium ethoxide. Theamount of the base to be used is generally 0.01-2, preferably 0.02-0.1equivalents, relative to NNTC.

In another embodiment, the amount of the base to be used is generally0.05-2 equivalents, preferably 0.1-1.0 equivalents, relative to NNTC.

The solvent is not particularly limited as long as the reactionproceeds. Examples thereof include methanol, ethanol, tetrahydrofuran,acetonitrile, and mixed solvents thereof. The amount of the solvent tobe used is generally 2-30 mL, preferably 3-5 mL, per 1 mmol of NNTC.

In another embodiment, the amount of the solvent to be used is generally5-30 mL, preferably 10-20 mL, per 1 mmol of NNTC.

The reaction temperature is generally 0-80° C., preferably 20-65° C.

The reaction time is generally 0.5-24 hr, preferably 1-2 hr.

(Step 6)

6-(4-Aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dioneor a salt thereof (hereinafter to also be referred to as NATP) can beproduced by subjecting NNTP to a reduction reaction. NATP is compound(II) wherein R² is an amino group. NNTP is compound (II) wherein R² is anitro group.

The reduction reaction can be carried out in the presence of a catalyst.The catalyst is not particularly limited as is long as it can be usedfor a catalytic reduction. Examples thereof include palladium on carbon,palladium hydroxide on carbon, platinum on carbon. The amount of thecatalyst to be used is generally 0.01-0.2 g, preferably 0.05-0.2 g, per1 g of NNTP.

An acid may be added to the reaction system for preferred progress ofthe reaction. Preferable examples of the acid include hydrochloric acid,hydrogen chloride/methanol solution, formic acid, acetic acid and thelike.

In the case of the catalytic reduction, the hydrogen pressure isgenerally 0.05-0.4 MPa, preferably 0.1-0.3 MPa.

The reduction reaction can also be carried out in a solvent. The solventis not particularly limited as long as the reaction proceeds. Examplesthereof include methanol, ethanol, tetrahydrofuran and the like. Theamount of the solvent to be used is generally 1-10 mL, preferably 4-6mL, per 1 mmol of NNTP.

The reaction temperature is generally 10-40° C., preferably 20-30° C.

The reaction time is generally 1-24 hr, preferably 3-5 hr.

1-{4-[1-(2,6-Difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof can be produced by reacting NATP with1,1′-carbonyldiimidazole or a salt thereof and methoxyamine or a saltthereof. NATP is compound (II) wherein R² is an amino group.

The amount of the 1,1′-carbonyldiimidazole or a salt thereof to be usedis generally 1.0-3.0 equivalents relative to NATP. The lower limit ispreferably 1.5 equivalents, more preferably 1.6 equivalents, relative toNATP, and the upper limit is 3.0 equivalents, more preferably 2.5equivalents, relative to NATP. The preferred range thereof is 1.6-2.5equivalents, more preferably 1.6-1.8 equivalents, relative to NATP.

The amount of the methoxyamine or a salt thereof (preferablymethoxyamine hydrochloride) to be used is generally 1.0-3.0 equivalentsrelative to 1,1′-carbonyldiimidazole or a salt thereof. The lower limitis preferably 1.05 equivalents, more preferably 1.1 equivalents,relative to 1,1′-carbonyldiimidazole or a salt thereof, and the upperlimit is 2.0 equivalents, more preferably 1.5 equivalents, relative to1,1′-carbonyldiimidazole or a salt thereof. The preferred range thereofis 1.1-1.7 equivalents, more preferably 1.1-1.5 equivalents, relative to1,1′-carbonyldiimidazole or a salt thereof.

By using 1,1′-carbonyldiimidazole or salt thereof and methoxyamine or asalt thereof in an amount of the above-mentioned lower limit or more,the production and residue of the related substance can be suppressed,and therefore,1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with higher purity can be obtained in higher yield.

In addition, by using 1,1′-carbonyldiimidazole or salt thereof andmethoxyamine or a salt thereof in an amount of the above-mentioned upperlimit or less, the reaction can be economically carried out.

A base may be used for preferred progress of the reaction. The base isnot particularly limited, and a base known per se can be used. Examplesthereof include triethylamine, diisopropylethylamine. The amount of thebase to be used is generally 0.5-3.0 equivalents, preferably 0.8-0.9equivalents, relative to NATP.

The reaction can also be carried out in a solvent. The solvent is notparticularly limited as long as the reaction proceeds. Examples thereofinclude acetonitrile, dimethylformamide, dimethylsulfoxide,dichloromethane and the like.

The amount of the solvent to be used is generally 1-10 mL, preferably2-3 mL, per 1 mmol of NATP.

The reaction temperature is generally 20-60° C., preferably 45-55° C.

The reaction time is generally 1-24 hr, preferably 1-2 hr.

(Step 8) (Purification of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a Salt Thereof) (Step 8-1) (Production of a Crystal of aTetrahydrofuran Solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a Salt Thereof)

A crystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof can be produced by recrystallizing1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof from tetrahydrofuran.

Alternatively, the above-mentioned crystal of tetrahydrofuran solvatecan also be produced by adding tetrahydrofuran to the reaction mixtureafter the completion of Step 7.

The amount of the tetrahydrofuran to be used is generally 1-20 mL,preferably 2-10 mL, per 1 g of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaninomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof.

The solution or suspension used for the production of the crystal oftetrahydrofuran solvate (hereinafter to also be referred to ascrystallization) is stirred generally at 20-80° C., preferably at 40-80°C., more preferably at 30-50° C.

In another embodiment, the solution used for the production of thecrystal of tetrahydrofuran solvate (hereinafter to also be referred toas crystallization) is stirred generally at 40-80° C., preferably at55-65° C.

The solution or suspension used for the crystallization may containwater, and the content of the water is generally greater than 0% and 50%or less, preferably 4-6%, relative to the crude crystals.

The crystallization time is generally 1-24 hr, preferably 1-2 hr.

By drying the obtained crystals according to a method known per se, acrystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof can be obtained. The drying can be carried out underreduced pressure or in air. The drying temperature is preferably 70° C.or less, more preferably 40-60° C.

(Step 8-2) (Production of a Crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a Salt Thereof)

A crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof can be produced by recrystallizing a crystal of atetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof using an alkyl alcohol and one solvent selected fromthe group consisting of dimethylsulfoxide, dimethylformamide anddimethylacetamide. By washing the obtained crystal with a solvent suchas tetrahydrofuran and the like, the crystal with higher purity can alsobe produced.

The amount of the dimethylsulfoxide, dimethylformamide ordimethylacetamide to be used is generally 1-5 mL, preferably 2-3 mL, per1 g of the crystal of tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof.

Examples of the alkyl alcohol include a C₁₋₆ alkyl alcohol (e.g.,ethanol, methanol, isopropyl alcohol) and the like. The alkyl alcohol ispreferably ethanol.

The amount of the alkyl alcohol to be used is generally 13-18 mL,preferably 14-16 mL, per 1 g of the crystal of tetrahydrofuran solvateof1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof.

In another embodiment, the amount of the alkyl alcohol to be used isgenerally 15-20 mL, preferably 16-18 mL, per 1 g of the crystal oftetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof.

Examples of the combination of the alkyl alcohol and one solventselected from the group consisting of dimethylsulfoxide,dimethylformamide and dimethylacetamide include a combination ofdimethylsulfoxide and ethanol, a combination of dimethylformamide andethanol, a combination of dimethylacetamide and ethanol, and the like.The combination is preferably dimethylsulfoxide and ethanol.

The crystallization solution or suspension which is subjected to therecrystallization is stirred generally at 10-50° C., preferably at15-40° C.

In another embodiment, the crystallization solution is stirred generallyat 20-50° C., preferably at 30-40° C.

The crystallization time is generally 1-72 hr, preferably 24-72 hr.

In another embodiment, the crystallization time is generally 1-64 hr,preferably 12-24 hr.

By drying the obtained crystals according to a method known per se, acrystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof can be obtained. The drying can be carried out underreduced pressure or in air. The drying temperature is preferably 70° C.or less, more preferably 40-60° C.

By producing a crystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof from1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof, and then recrystallizing the obtained crystal oftetrahydrofuran solvate using the above-mentioned particular solvents,the contents of the Related Substances 1-3 described in thebelow-mentioned Examples can be decreased, and therefore,1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with higher purity can be obtained.

The salt of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureais not particularly limited as long as it is acceptable as a medicament.Examples thereof include salts with an inorganic acid (e.g.,hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid,phosphoric acid etc.), and salts with an organic acid (e.g., formicacid, acetic acid, trifluoroacetic acid, fumaric acid, oxalic acid,maleic acid, citric acid, succinic acid, malic acid, methanesulfonicacid, benzenesulfonic acid, p-toluenesulfonic acid etc.).

1-{4-[1-(2,6-Difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof is useful for the prophylaxis or treatment of diseasescaused by gonadotropin releasing hormone (e.g., endometriosis, uterinefibroid and prostate cancer), and can be used for the prophylaxis ortreatment of the above-mentioned diseases according to the methoddescribed in WO 00/56739.

EXAMPLES

The present invention is explained in detail in the following byreferring to Reference Examples, Examples and Experimental Examples andwhich are merely exemplified and not to be construed as limitative, andthe invention may be changed within the scope of the present invention.In the following Examples, the “room temperature” generally means about10° C. to about 35° C. The ratios indicated for mixed solvents arevolume mixing ratios, unless otherwise specified. % means wt %, unlessotherwise specified.

In the following Examples, proton nuclear magnetic resonance spectrum(¹H NMR) was measured by Varian Mercury-300 type nuclear magneticresonance apparatus (300 MHz) using tetramethylsilane as the internalstandard. As splitting patterns, singlet, doublet, triplet and multipletare abbreviated as s, d, t and m, respectively. The results of theelemental analysis were within ±0.4% of the calculated value. PowderX-ray was measured by D8 ADVANCE (Bruker AXS). High-performance liquidchromatography (HPLC) was measured under condition described in eachReference Example and Example.

Reference Example 1 (Production of 3-amino-6-methoxypyridazinehydrochloride)

Methanol (400 mL), 3-amino-6-chloropyridazine (64.0 g, 0.494 mol) and28% sodium methoxide methanol solution (114.5 g, 0.593 mol, 1.2 eq) werecharged into high pressure reactor, and the mixture was reacted atinternal temperature of 130° C. for 8 hr (internal pressure: about 0.7MPa). The reaction mixture was cooled, conc. hydrochloric acid (12.8 mL)was added dropwise thereto at the temperature not exceeding 40° C., andthe mixture was stirred for 20 min. Then, 25% aqueous ammonia (14.9 mL)was added dropwise thereto at the temperature not exceeding 40° C. Thereaction mixture was concentrated to about 150 mL under reducedpressure, and isopropyl alcohol (350 mL) was added thereto. Again, themixture was concentrated to about 150 mL under reduced pressure,isopropyl alcohol (350 mL) was added thereto, and the mixture wasstirred for 30 min. The precipitated salt was filtered off, and to thefiltrate was added dropwise conc. hydrochloric acid (38.2 mL) at thetemperature not exceeding 40° C. The mixture was concentrated to about200 mL under reduced pressure, and isopropyl alcohol (300 mL) was addedthereto. Again, the mixture was concentrated to about 200 mL underreduced pressure, isopropyl alcohol (300 mL) was added thereto, and themixture was stirred for 30 min. The precipitated crystals were collectedby filtration, washed with isopropyl alcohol (50 mL), and dried at 50°C. under reduced pressure until the weight became constant to give acrystal of 3-amino-6-methoxypyridazine hydrochloride (66.9 g, yield:83.8%, HPLC area percent: 100%).

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC-Pack ODS-A A-302, 4.6 mm i.d.×150

mobile phase: 0.05M KH₂PO₄/CH₃CN=8/2 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time: 3-amino-6-methoxypyridazine (1.9 min),3-amino-6-chloropyridazine (2.6 min)

Reference Example 2 (Production of ethyl2-amino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate)

Toluene (200 mL), 4-nitrophenylacetic acid (100.0 g, 0.552 mol) andN,N′-dimethylformamide (0.42 mL) were heated with stirring, and thionylchloride (78.8 g, 0.662 mol, 1.2. eq) was added dropwise thereto atinternal temperature of 45±5° C. The mixture was stirred at internaltemperature of 45±5° C. for 1 hr, and concentrated to about 238 mL underreduced pressure to give an acid chloride solution. Separately, toluene(500 mL), magnesium diethoxide (75.8 g, 0.662 mol, 1.2 eq) and diethylmalonate (106.1 g, 0.662 mol, 1.2 eq) were stirred at internaltemperature of 65±5° C. for 0.5 hr, and the mixture was cooled tointernal temperature of 40° C. or less. To the solution was addeddropwise the total amount of the previously prepared acid chloridesolution at internal temperature of 35±5° C., the mixture was stirred atthe same temperature for 0.5 hr, and cooled to internal temperature of30° C. or less, and 2N hydrochloric acid (413 g) was added dropwisethereto at internal temperature of 2515° C. The mixture was leftstanding, and the organic layer was separated, washed with 10% brine(400 g), and concentrated to about 250 mL under reduced pressure. To theresidue were added acetic acid (176.0 g), water (112 mL) and conc.sulfuric acid (39.0 g), and the mixture was heated with reflux for 4 hrwhile evaporating volatiles. The mixture was cooled to internaltemperature of 15±5° C., ethyl acetate (450 mL) was added thereto, andthe pH of the mixture was adjusted to 7.0 with 5N aqueous sodiumhydroxide solution at internal temperature of 10-30° C. The mixture wasleft standing, and the organic layer was separated, washed with 10%brine (100 mL), and concentrated to about 150 mL under reduced pressure.To the residue were added ethanol (240 mL), ethyl cyanoacetate (68.7 g,0.607 mol, 1.1 eq) and sulfur (19.5 g, 0.607 mol, 1.1 eq), and thenn-butylamine (20.2 g, 0.276 mol, 0.5 eq) was added dropwise thereto atinternal temperature of 20-45° C. The mixture was stirred at internaltemperature of 45±5° C. for 2 hr, cooled to internal temperature of25±5° C., and stirred at the same temperature for 1 hr. The crystalswere collected by filtration, washed with ethanol (200 mL), and driedunder reduced pressure at 50° C. or less to give ethyl2-amino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate (134.9 g,yield: 79.8%, HPLC area percent: 99.2%) as red crystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=3/7 (v/v)

flow rate: 1.0 mL/min.

measurement time: 45 min

analysis temperature: 25° C.

retention time: ethyl2-amino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate (5.9 min)

Reference Example 3 (Production of ethyl2-ethoxycarbonylamino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate)

Ethyl 2-amino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate (130.0g, 0.424 mol) was suspended in toluene (390 mL), ethyl chloroformate(92.1 g, 0.849 mol, 2.0 eq) was added dropwise thereto while heatingwith reflux, and the mixture was stirred for 2 hr while heating withreflux. The mixture was cooled to internal temperature of 55±5° C.,ethanol (1170 mL) was added dropwise thereto at the same temperature,and the mixture was cooled to internal temperature of 5±5° C., andstirred at the same temperature for 1 hr. The crystals were collected byfiltration, washed with ethanol (260 mL), and dried at 45° C. underreduced pressure to give ethyl2-ethoxycarbonylamino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(154.2 g, yield: 96.1%, HPLC area percent: 99.9%) as yellow crystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=3/7 (v/v)

flow rate: 1.0 mL/min.

measurement time: 45 min

analysis temperature: 25° C.

retention time: ethyl2-amino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate (5.9 min),ethyl2-ethoxycarbonylamino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(16.5 min)

Reference Example 4 (Production of ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate)

Ethyl2-ethoxycarbonylamino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(150.0 g, 0.396 mol) was suspended in N,N′-dimethylacetamide (450 mL),and potassium carbonate (60.3 g, 0.436 mol, 1.1 eq) and 35%2,6-difluorobenzyl bromide/acetonitrile solution (257.9 g, 0.436 mol,1.1 eq) were added thereto. The mixture was heated with stirring atinternal temperature of 85±5° C. for 2 hr, and cooled to internaltemperature of 55±5° C., and ethyl acetate (1200 mL) and water (750 mL)were added thereto. The mixture was left standing, and the organic layerwas separated, washed with water (750 mL), and concentrated to about 420mL under reduced pressure. To the residue was added heptane (945 mL),and the mixture was stirred at internal temperature of 45±5° C. for 1hr, and then at internal temperature of 5±5° C. for 1 hr. The crystalswere collected by filtration, washed with ethyl acetate/heptane (1/3,300 mL) of 5±5° C., and dried at 45±5° C. under reduced pressure to giveethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(190.7 g, yield: 95.5%, HPLC area percent: 99.9%) as pale yellowcrystals.

<HPLC Condition>

detector: ultraviolet absorptiameter (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=3/7 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time: ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(10.7 min), ethyl2-ethoxycarbonylamino-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(16.4 min)

Example 1 (Production of ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate)

Ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(1100.0 g, 2.180 mol) was suspended in a mixed solvent of ethyl acetate(8.8 L) and trifluoromethylbenzene (880 mL), N-bromosuccinimide (NBS,485.1 g, 2.725 mol, 1.25 eq) and 2,2′-azobis(2,4-dimethylvaleronitrile)(V-65, 54.2 g, 0.218 mol, 0.1 eq) were added thereto. The reactionmixture was heated with stirring at 65-75° C. for 40 min. The reactionmixture was cooled to 25±5° C., and washed twice with city water (4.3L). The ethyl acetate layer was concentrated to about 4 L under reducedpressure. Ethanol (3 L) was added thereto, and the mixture wasconcentrated to about 4 L under reduced pressure. Again, ethanol (3 L)was added thereto, and the mixture was concentrated to about 4 L underreduced pressure. Heptane (1.76 L) was added thereto, and the mixturewas stirred at 25±5° C. for 30 min. Again, heptane (1.32 L) was addedthereto, and the mixture was stirred at 5±5° C. for 1 hr. The crystalswere collected by filtration, washed with ethanol/heptane (1/2, 1.76 L),and dried at 45±5° C. under reduced pressure to give ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate(1171 g, yield: 92.1%, HPLC area percent: 92.9%) as pale yellowcrystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=3/7 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time: ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(11.0 min), ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate(12.3 min)

Example 2 (Production of ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylate)

Dimethylamine hydrochloride (2.10 g, 25.71 mmol, 1.5 eq) was suspendedin N,N′-dimethylformamide (DMF, 55 mL), triethylamine (4.51 g, 44.57mmol, 2.6 eq) was added thereto, and the mixture was stirred at 25±5° C.for 30 min. The mixture was cooled to 5±5° C., and ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate(10 g, 17.14 mmol) was added thereto, and the container used for thecompound was washed with DMF (5 mL). The reaction mixture was stirred at15±5° C. for 1 hr. Ethanol (20 mL) was added thereto at 20±10° C., andthe mixture was warmed to internal temperature of 40±5° C. City water(25 mL) was added thereto at internal temperature of 40±5° C., and themixture was stirred at the same temperature for 1 hr, and then at 25±5°C. for 1 hr. The crystals were collected by filtration, washed withethanol/city water (4/1, 15 mL), and dried at 50±5° C. under reducedpressure to give ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylate(8.41 g, yield: 89.6%, HPLC area percent: 99.6%) as yellow crystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=3/7 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time: ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylate(2.3 min), ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate(13.1 min)

¹H-NMR (CDCl₃) δ: 1.10-1.30 (3H, m), 1.31 (3H, t, J=7.2 Hz), 2.07 (6H,s), 3.51 (2H, s), 4.10-4.30 (2H, m), 4.23 (2H, q, J=7.2 Hz), 5.02 (2H,s), 6.85 (2H, t, J=8.0 Hz), 7.66 (2H, d, J=9.0 Hz), 8.24 (2H, d, J=9.0Hz).

Example 3 (Production of2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid)

Ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylate(8.0 g, 14.61 mmol) was suspended in a mixed solvent of ethanol (72 mL)and city water (20.8 mL), 48% aqueous potassium hydroxide solution (2.56g, 21.92 mmol, 1.5 eq) was added thereto, and the mixture was stirred at60±5° C. for 5 hr. The reaction mixture was cooled to 25±5° C., and thepH of the mixture was adjusted to 6.0-7.0 with 6N hydrochloric acid. Themixture was concentrated to about 28 mL at 50° C. or less under reducedpressure, and ethanol (4 mL) and ethyl acetate (4 mL) were added theretoat internal temperature of 40±5° C. Then, city water (48 mL) was addedthereto at the same temperature, and the mixture was stirred at the sametemperature for 1 hr. The mixture was cooled to internal temperature of25±5° C., and stirred at the same temperature for 3 hr. The crystalswere collected by filtration, washed successively with ethanol/citywater (1/9, 24 mL) and cooled ethyl acetate (24 mL), and dried at 45±5°C. under reduced pressure to give2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid (6.82 g, yield: 89.9%, HPLC area percent: 98.7%) as yellowcrystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=6/4 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time:2-[(2,6-difluorobenzyl)ethoxycarbonylamine]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid (8.4 min), ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylate(14.8 min)

¹H-NMR (CDCl₃) δ: 1.10-1.40 (3H, m), 2.37 (6H, s), 3.72 (2H, s),4.10-4.35 (2H, m), 5.07 (2H, s), 6.84 (2H, t, J=7.5 Hz), 7.15-7.30 (1H,m), 7.42 (2H, d, J=8.8 Hz), 8.29 (2H, d, J=8.8 Hz).

Example 4 (Production of ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate)

Under a nitrogen atmosphere,2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid (6.5 g, 12.51 mmol) and 3-amino-6-methoxypyridazine hydrochloride(2.43 g, 15.01 mmol, 1.2 eq) were added to N,N′-dimethylacetamide (DMAc,29.25 mL), and then ethyldiisopropylamine (4.03 g, 31.28 mmol, 2.5 eq)was added thereto at 25±15° C. The mixture was warmed to internaltemperature of 55±5° C., and stirred for 30 min. 50.5% Propylphosphonicanhydride (T3P) ethyl acetate solution (9.55 g, 15.01 mmol, 1.2 eq) wasadded dropwise thereto at internal temperature of 60° C. or less, andthe container used for the reagent was washed with DMAc (3.25 mL). Themixture was stirred at internal temperature of 55±5° C. for 1 hr. Thereaction mixture was cooled to 25±5° C., and city water (48.75 mL) wasadded dropwise thereto at the same temperature. Then, 8N aqueous sodiumhydroxide solution was added thereto at 25±5° C. while vigorouslystirring, and the pH of the mixture was adjusted to 7.5-8.5, and themixture was stirred at 25±5° C. for 30 min. The crystals were collectedby filtration, washed with methanol (26 mL), and dried at 40±5° C. underreduced pressure until the weight became constant to give ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate(7.61 g, yield: 97.0%, HPLC area percent: 98.5%) as yellow crystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.02M KH₂PO₄/CH₃CN=4/6 (v/v)

flow rate: 1.0 mL/min.

measurement time: 40 min

analysis temperature: 25° C.

retention time: 3-amino-6-methoxypyridazine (1.7 min),2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-dimethylaminomethyl-5-(4-nitrophenyl)thiophene-3-carboxylicacid (2.5 min), ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate(15.0 min)

¹H-NMR (CDCl₃) δ: 1.10-1.40 (3H, m), 2.20 (6H, s), 3.51 (2H, s), 4.10(3H, m), 4.20-4.35 (2H, m), 5.03 (2H, s), 6.70-6.80 (2H, m), 6.99 (1H,d, J=9.5 Hz), 7.10-7.20 (1H, m), 7.45-7.55 (2H, m), 8.25-8.35 (2H, m),8.54 (1H, d, J=9.5 Hz).

Example 5 (Production of1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionehydrochloride)

Ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate(7.5 g, 11.97 mmol), methanol (187.5 mL, 25 v/w), tetrahydrofuran (12.75mL, 1.7 v/w) and 28% sodium methoxide methanol solution (0.46 g, 2.39mmol, 0.2 eq) were stirred at 60±5° C. for 1 hr. The mixture was cooledto 25±5° C., conc. hydrochloric acid (2.87 g, 28.73 mmol, 2.4 eq) wasadded dropwise thereto, and the mixture was stirred for 20 min.Isopropyl alcohol (75 mL) was added thereto, and the mixture was stirredat 25±5° C. for 20 min, and then at 5±5° C. for 40 min. The crystalswere collected by filtration, washed with cooled methanol/isopropylalcohol (1/1, 22.5 mL), and dried at internal temperature of 60° C. orless (external temperature 55±5° C.) under reduced pressure to give1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionehydrochloride (2.24 g, yield: 98.0%, HPLC area percent: 99.9%) as yellowcrystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.02M KH₂PO₄/CH₃CN=4/6 (v/v)

flow rate: 1.0 mL/min.

measurement time: 40 min

analysis temperature: 25° C.

retention time: ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate(15.0 min),1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(2.5 min)

¹H-NMR (CDCl₃) δ: 2.20 (6H, s), 3.72 (2H, s), 4.19 (3H, s), 5.38 (2H,brs), 6.95 (2H, t, J=8.2 Hz), 7.14 (1H, d, J=9.0 Hz), 7.20-7.35 (1H, m),7.42 (1H, d, J=9.0 Hz), 7.89 (2H, d, J=8.8 Hz), 8.28 (2H, d, J=8.8 Hz).

Example 6 (Production of6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(in the Present Specification, to Also be Referred to as RS-2 (RelatedSubstance 2)))

To1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionehydrochloride (80.0 g, 129.66 mmol) were added methanol (640 mL) andconc. hydrochloric acid (10.8 g, 103.68 mmol, 0.8 eq). 10% Pd—C NX type(8.0 g, containing 50% water) was added thereto under nitrogenatmosphere, and the mixture was stirred at 25±5° C. for 4 hr underhydrogen pressure of 0.2±0.1 MPa. The pH of the mixture was adjusted to6.5±0.5 with triethylamine at 25-5° C. Activated carbon (Shirasagi A,4.0 g) was added thereto, and the mixture was stirred for 20-60 min. Theactivated carbon and catalyst were filtered off, and washed withmethanol (160 mL). The filtrate was warmed to 40±5° C., and the pH ofthe mixture was adjusted to 8.0-8.5 with triethylamine. The mixture wasaged with stirring at 40±5° C. for about 30 min, cooled to 5±5° C., andaged with stirring for about 2 hr. The crystals were collected byfiltration, washed with methanol (160 mL), and dried at 45±5° C. underreduced pressure until the weight became constant to give an almostwhite crystal of6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(60.06 g, yield: 84.1%, HPLC area percent: 99%).

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄ (pH7.0 by 10% KOH)/CH₃CN=55/45 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time:6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(4.0 min),1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(16 min)

¹H-NMR (CDCl₃) δ: 2.09 (6H, s), 3.40-3.70 (2H, br), 3.78 (2H, s), 4.14(3H, s), 5.31 (2H, brs), 6.66 (2H, d, J=8.6 Hz), 6.88 (2H, t, J=7.6 Hz),7.07 (1H, d, J=9.2 Hz), 7.15-7.25 (1H, so m), 7.27 (2H, d, J=8.0 Hz),7.38 (11, d, J=9.2 Hz).

Example 7 (Production of a Crystal of a Tetrahydrofuran Solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea)

Acetonitrile (30 mL) and 1,1′-carbonyldiimidazole (CDI, 5.01 g, 30.90mmol, 1.7 eq) were charged into a reactor, and the mixture was stirred.Triethylamine (1.56 g, 15.42 mmol, 0.85 eq) was added thereto withstirring, and cooled to internal temperature of 10±5° C. Methoxyaminehydrochloride (2.90 g, 34.72 mmol, 1.91 eq) was added thereto withstirring in some portions at internal temperature of 30° C. or less, andthe container used for the reagent was washed with acetonitrile (5 mL).The mixture was stirred at internal temperature of 25±5° C., and afterconfirming the dissolution of the mixture, the solution was stirred foradditional 10 min or more. Then,6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(10.00 g, 18.16 mmol) was added thereto with stirring, and the containerused for the reagent was washed with acetonitrile (5 mL). The reactionmixture was warmed to internal temperature of 50±5° C., and stirred atthe same temperature for 2 hr to give a reaction mixture (hereinafter tobe referred to as Reaction Mixture A). Triethylamine (2.35 g, 23.22mmol, 1.28 eq) was added thereto with stirring at internal temperatureof 505° C. City water (40 mL) was added dropwise thereto at internaltemperature of 40-55° C., the mixture was stirred for 1 hr, and citywater (100 mL) was added dropwise again thereto at internal temperatureof 40-55° C. The mixture was aged with stirring at internal temperatureof 25±5° C. for 1 hr or more. The crystals were collected by filtration,and washed with a mixed solvent of city water (16 mL) and acetonitrile(4 mL) to give wet crystals. To the wet crystals was addedtetrahydrofuran (50 mL), and the mixture was warmed to internaltemperature of 60±5° C., and stirred at the same temperature for about 1hr. The mixture was cooled to internal temperature of 5±5° C., and agedwith stirring at the same temperature for about 2 hr. The crystals werecollected by filtration, washed with tetrahydrofuran (10 mL), and driedat external temperature 50±10° C. under reduced pressure to give acrystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(11.49 g, yield 90.9%).

¹H-NMR (CDCl₃) δ: 1.80-1.90 (4H, m), 2.13 (6H, s), 3.60-3.80 (6H, m),3.82 (3H, s), 4.18 (3H, s), 5.35 (2H, brs), 6.92 (2H, t, J=8.2 Hz), 7.12(1H, d, J=8.8 Hz), 7.20-7.60 (7H, m), 7.65 (1H, s).

Anal Calcd for C₃₃H₃₅F₂N₇O₆S: C, 56.97; H, 5.07; N, 14.09. Found: C,56.81; H, 5.17; N, 13.92.

The powder X-ray diffraction pattern of the above-mentioned crystal oftetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureais shown in FIG. 1 .

<Measurement Condition for Powder X-Ray Diffraction>

tube voltage: 40 kV

tube current: 40 mA

gate time: 0.2 sec/step

step width: 0.02°

scanning field: 2θ-3-40°

In addition, the characteristic peaks of the powder X-ray diffractionpattern are shown in Table 1.

TABLE 1 2θ (°) d value (Å) relative intensity (%) 7.285 12.125 85.98.302 10.642 40.2 10.597 8.342 72.4 13.605 6.504 41.1 15.292 5.790 100.018.792 4.718 44.9 23.059 3.854 31.7 25.144 3.539 20.4 29.294 3.047 18.1

Example 8 (Production of a Crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea)

Dimethylsulfoxide (DMSO, 20 mL) and a crystal of a tetrahydrofuransolvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(8.93 g) were charged into a reactor, and the mixture was dissolved bywarming to internal temperature of 35±5° C. After confirming thedissolution of the mixture, ethanol (20 mL) was added thereto atinternal temperature of 35±5° C. The mixture was filtered through a dustremoval filter, and washed with ethanol (8 mL). To the filtrate wasadded ethanol (112 mL) at internal temperature of 35±5° C., and themixture was stirred at internal temperature of 35±5° C. for 1 hr ormore, cooled to internal temperature of 25±5° C., and stirred again atthe same temperature for 12 hr or more. The crystals were collected byfiltration, washed with ethanol (16 mL), and dried at externaltemperature 50±10° C. under reduced pressure to give1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(7.33 g, yield 91.6%) as white crystals.

The powder X-ray diffraction pattern of the above-mentioned whitecrystal is shown in FIG. 2 .

<Measurement Condition for Powder X-Ray Diffraction>

tube voltage: 40 kV

tube current: 40 mA

gate time: 0.2 sec/step

step width: 0.02°

scanning field: 2θ-3-40°

In addition, the characteristic peaks of the powder X-ray diffractionpattern are shown in Table 2.

TABLE 2 2θ (°) d value (Å) relative intensity (%) 7.384 11.963 29.18.932 9.893 82.6 9.933 8.898 40.9 12.076 7.323 48.8 16.607 5.334 100.017.328 5.114 55.8 22.202 4.001 41.5 22.761 3.904 37.2 27.422 3.245 18.4

Example 9

The experiment was carried out in the same manner as in Example 7,except that the equivalents (eq) of 1,1′-carbonyldiimidazole (CDI) andmethoxyamine hydrochloride were changed. The contents of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(in the table, to be referred to as “Compound A”) and RS-2 in ReactionMixture A obtained in the above-mentioned experiment are shown in Table4. The equivalent of CDI in the table means one relative to NATP, andthe equivalent of methoxyamine hydrochloride means one relative to CDI.

HPLC measurement condition in Example 9 and Experimental Example 1 isshown in the following.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 230 nm)

column: Sunfire C18 S-3.5 μm, 4.6 mm i.d.×10 cm (manufactured by Waters)

mobile phase: (A) a mixed solvent of 0.05 mol/L phosphorate buffersolution (pH2.0)/acetonitrile (31:9 (volume ratio))

(B) a mixed solvent of 0.05 mol/L phosphorate buffer solution(pH2.0)/acetonitrile (12:13 (volume ratio))

gradient program (linear)

TABLE 3 Time (min) A solution (%) B solution (%) 0 (injection) 100 0 20100 0 55 0 100 55.1 100 0 65 100 0

flow rate: 1.0 mL/min.

measurement time: 60 min

analysis temperature: 40° C.

retention time:6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(7.3 min),1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(15.5 min)

TABLE 4 methoxyamine Compound A RS-2 NATP CDI hydrochloride HPLC areapercent (%) 1eq 1.5eq 1.127eq 93.38% 4.45% 1eq 1.6eq 1.125eq 96.70%0.25% 1eq 1.7eq 1.125eq 95.15% 0.20% 1eq 1.8eq 1.125eq 93.89% 0.22% 1eq2.0eq 1.125eq 92.56% 0.23% 1eq 2.5eq 1.124eq 90.28% 0.20%

As can be seen in Table 4, it was found that, in the production shown inExample 7,1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureawith high quality, which has low content of RS-2, can be obtained byusing CDI of 1.6 to 2.5 equivalents relative to NATP and methoxyaminehydrochloride of 1.1 to 1.5 equivalents relative to CDI.

Experimental Example 1

The contents of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(in the table, to be referred to as “Compound A”) and the relatedsubstances (specifically RS-1, RS-2 and RS-3) in each crystal obtainedExamples 7 and 8 were measured. The results are shown in Table 5.

TABLE 5 HPLC area percent (%) Sample RS-1 RS-2 Compound A RS-3 a wetcrystal of 0.10 0.16 99.37 0.08 Example 7 a crystal of a 0.04 0.07 99.750.02 tetrahydrofuran solvate of Example 7 a white crystal of 0.02 0.0599.81 <0.02 Example 8

As can be seen in Table 5, the contents of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureain the crystal of tetrahydrofuran solvate obtained in Example 7 and thewhite crystal obtained in Example 8 are high as compared with the wetcrystal obtained in Example 7. From this evidence, it was found that1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureawith high quality, which has low contents of the related substances, canbe obtained by the methods described in Example 7 and Example 8.

Example 10 (Production of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-2,4-dioxo-3-(6-oxo-1,6-dihydropyridazin-3-yl)-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(in the Present Specification, to Also be Referred to as RS-1 (RelatedSubstance 1)))

1-{4-[1-(2,6-Difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(0.50 g, 0.80 mmol) was dissolved in DMSO (1.5 mL), and conc.hydrochloric acid (0.32 g, 3.2 mmol) was added thereto. The reactionmixture was stirred at 80° C. for 2 hr. Aqueous sodium bicarbonatesolution (0.27 g, 3.2 mmol) and water (3 mL) were added thereto at roomtemperature, and the precipitate was collected by filtration, and washedwith water (30 mL), and dried at 50° C. under reduced pressure to give acrystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-2,4-dioxo-3-(6-oxo-1,6-dihydropyridazin-3-yl)-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(0.19 g, 39%).

¹H-NMR (CDCl₃) δ: 2.06 (6H, s), ca.3.54 (1H, m), ca.3.63 (1H, m), 3.65(3H, s), ca.5.18 (1H, m), ca.5.40 (1H, m), 7.07 (1H, d, J=9.8 Hz),ca.7.14 (1H, m), ca.7.47 (1H, m), ca.7.51 (1H, m), ca.7.52 (2H, m),ca.7.72 (2H, m), 9.08 (1H, s), 9.63 (1H, s), 13.29 (111, s).

IR (KBr): 1719, 1676, 1591, 1528, 1470, 1410, 1331, 1034 cm⁻¹.

ESI-MS m/z: 610.17 [M+H]⁺, 608.15 [M−H]⁻.

Anal Calcd for C₂₇H₂₄F₂N₆O₃S·0.1H₂O: C, 58.71; H, 4.42; N, 15.21. Found:C, 58.43; H, 4.39; N, 15.19.

Example 11 (Production ofN-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-N,N′-dimethoxydicarbonimidicdiamide (in the Present Specification, to Also be Referred to as RS-3(Related Substance 3)))

RS-3 was separated from crude1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaby HPLC, and the structure was determined by the following spectrumdata.

1H-NMR (CDCl₃) δ: 2.05 (6H, s), ca.3.54 (1H, m), ca.3.67 (1H, m), 3.70(3H, s), 3.80 (3H, s), 4.10 (3H, s), ca.5.22 (1H, m), ca.5.39 (1H, m),ca.7.14 (2H, m), ca.7.46 (1H, m), ca.7.47 (1H, m), ca.7.62 (2H, m),ca.7.64 (2H, m), ca.7.76 (1H, m), 10.30 (1H, s), 11.34 (1H, s).

IR (KBr): 1714, 1674, 1591, 1528, 1460, 1410, 1306, 1036 cm⁻¹.

ESI-MS m/z: 697.20 [M+H]⁺, 719.18 [M+Na]⁺.

Anal Calcd for C₃₁H₃₀F₂N₈O₇S·1.0H₂O: C, 52.10; H, 4.51; N, 15.68. Found:C, 52.17; H, 4.52; N, 15.78.

Example 12 (Production of ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate)

Ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(50 g, 99.11 mmol) was suspended in a mixed solvent of ethyl acetate(300 mL) and trifluoromethylbenzene (40 mL), and the mixture was purgedwith nitrogen. A suspension of N-bromosuccinimide (NBS, 22.05 g, 123.89mmol, 1.25 eq) and 2,2′-azobis(2,4-dimethylvaleronitrile) (V-65, 1.97 g,7.93 mmol, 0.08 eq) in ethyl acetate (90 mL) was added thereto atinternal temperature of 70±5° C., and the container used for thesuspension was washed with ethyl acetate (10 mL).

The reaction mixture was heated with stirring at 65-75° C. for 40 min.The reaction mixture was cooled to 25±5° C., and washed twice with citywater (195 mL). The ethyl acetate layer was concentrated to about 165 mLunder reduced pressure. Ethanol (135 mL) was added thereto, and themixture was concentrated to about 155 mL under reduced pressure. Ethanol(135 mL) was added again thereto, and then heptane (130 mL) was addedthereto, and the mixture was stirred at 25±5° C. for 30 min. Heptane(100 mL) was added again thereto, and the mixture was stirred at 5±5° C.for 1 hr. The crystals were collected by filtration, washed withethanol/heptane (1/2, 80 mL), and dried at 45±5° C. under reducedpressure to give ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate(50.4 g, yield: 92.1%, HPLC area percent: 94.3%) as pale yellowcrystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄/CH₃CN=3/7 (v/v)

flow rate: 1.0 mL/min.

measurement time: 40 min

analysis temperature: 25° C.

retention time: ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate(11.5 min), ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate(13 min)

Example 13 (Production of1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionehydrochloride)

Ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-ylcarbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate(30.0 g, 47.88 mmol) was suspended in acetonitrile (210 mL), 28% sodiummethoxide methanol solution (0.46 g, 2.39 mmol, 0.05 eq) was addedthereto at internal temperature of 25±5° C., and the container used forthe reagent was washed with methanol (0.3 mL). The mixture was stirredat internal temperature of 25±5° C. for 1 hr, and the crystals werecollected by filtration, and washed with acetonitrile (60 mL) to give1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione.

Methanol (90 mL), isopropyl alcohol (150 mL) and conc. hydrochloric acid(5.49 g, 52.66 mmol, 1.1 eq) were charged into a reactor, the totalamount of1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionewas added thereto at internal temperature of 25±5° C., and the containerused for the compound was washed with isopropyl alcohol (30 mL). Themixture was stirred at internal temperature of 25±5° C. for 0.5 hr,cooled to internal temperature of 55° C., and stirred at the sametemperature for 1 hr. The crystals were collected by filtration, washedwith methanol/isopropyl alcohol (1/2, 60 mL, cooled to 5±5° C.), anddried at 50±5° C. under reduced pressure to give1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionehydrochloride (29.3 g, yield: 99.2%, HPLC area percent: 99.8%) as yellowcrystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.02M KH₂PO₄/CH₃CN=4/6 (v/v)

flow rate: 1.0 mL/min.

measurement time: 40 min

analysis temperature: 25° C.

retention time: ethyl(2,6-difluorobenzyl)-[4-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl-carbamoyl)-5-(4-nitrophenyl)thiophen-2-yl]carbamate(10.5 min),1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(2.9 min)

Example 14 (Production of6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(in the Present Specification, to Also be Referred to as RS-2 (RelatedSubstance 2)))

To1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dionehydrochloride (9.0 g, 14.59 mmol) were added methanol (72 mL) and conc.hydrochloric acid (1.22 g, 11.67 mmol, 0.8 eq). 10% Pd—C NX type (0.9 g,containing 50% water) was added thereto under nitrogen atmosphere, andthe mixture was stirred at 25±5° C. for 4 hr under hydrogen pressure of0.2±0.1 MPa. The pH of the reaction mixture was adjusted to 6.5±0.5 withtriethylamine at 25±5° C. Activated carbon (Shirasagi A, 0.45 g) wasadded thereto, and the mixture was stirred for 20-60 min. The activatedcarbon and catalyst were filtered off, and washed with methanol (18 mL).The filtrate was warmed to 40±5° C., and the pH of the mixture wasadjusted to 8.0-8.5 with triethylamine. The mixture was aged withstirring at 40±5° C. for about 30 min, cooled to 55° C., and aged withstirring for 1 hr. The crystals were collected by filtration, washedtwice with methanol (18 mL), and dried at 45±5° C. under reducedpressure until the weight became constant to give an almost whitecrystal of6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(6.93 g, yield: 86.3%, HPLC area percent: 99.5%).

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 254 nm)

column: YMC ODS-A A-302, 4.6 mm i.d.×150 mm

mobile phase: 0.05M KH₂PO₄ (pH7.0 by 10% KOH)/CH₃CN=55/45 (v/v)

flow rate: 1.0 mL/min.

measurement time: 30 min

analysis temperature: 25° C.

retention time:6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(4.8 min),1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-6-(4-nitrophenyl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(16 min)

Example 15 (Production of a Crystal of a Tetrahydrofuran Solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea)

Acetonitrile (60 mL) and 1,1′-carbonyldiimidazole (CDI, 10.01 g, 61.75mmol, 1.7 eq) were charged into a reactor, and the mixture was stirred.Triethylamine (3.12 g, 30.88 mmol, 0.85 eq) was added thereto withstirring, and the mixture was cooled to internal temperature of 10±5° C.Methoxyamine hydrochloride (5.79 g, 69.38 mmol, 1.91 eq) was addedthereto with stirring in some portions at internal temperature of 30° C.or less, and the container used for the reagent was washed withacetonitrile (10 mL). The mixture was stirred at internal temperature of25±5° C., and after confirming the dissolution of the mixture, thesolution was stirred for additional 10 min or more.6-(4-Aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(20.00 g, 36.33 mmol) was added thereto with stirring, and the containerused for the reagent was washed with acetonitrile (10 mL). The reactionmixture was warmed to internal temperature of 50±5° C., and stirred atthe same temperature for 1 hr to give a reaction mixture. Again,triethylamine (4.70 g, 46.50 mmol, 1.28 eq) was added thereto withstirring at internal temperature of 50±5° C. City water (80 mL) wasadded dropwise thereto at internal temperature of 40-55° C., and themixture was stirred for 1 hr, and city water (200 mL) was added dropwisethereto at internal temperature of 40-55° C. The mixture was aged withstirring at internal temperature of 25±5° C. for 1 hr or more. Thecrystals were collected by filtration, washed with a mixed solvent ofcity water (32 mL) and acetonitrile (8 mL), and dried at 50±10° C. underreduced pressure to give crude crystals (21.92 g). The crude crystals(21.0 g) were suspended in tetrahydrofuran (100 mL), and water was addedthereto so that the water content was 5% relative to the crude crystals.The mixture was warmed to internal temperature of 40±5° C., and stirredat the same temperature for about 1 hr. The mixture was cooled tointernal temperature of 5±5° C., and stirred at the same temperature for1 hr. The crystals were collected by filtration, washed withtetrahydrofuran (40 mL), and dried at external temperature 50±10° C.under reduced pressure to give a crystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(22.56 g, yield 93.2%, HPLC area percent: 99.8%).

Example 16 (Production of a crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea)

Dimethylsulfoxide (20 mL) and a crystal of a tetrahydrofuran solvate of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(11.16 g) were charged into a reactor, and the mixture was dissolved bywarming to internal temperature of 35±5° C. After confirming thedissolution of the mixture, the mixture was filtered through a dustremoval filter, and washed with dimethylsulfoxide (5 mL). Ethanol (55mL) was added thereto at internal temperature of 35±5° C., and then seedcrystals (10 mg) obtained in Reference Example 5 were added thereto, andthe mixture was stirred at internal temperature of 35±5° C. for 17 hr.Ethanol (120 mL) was added dropwise thereto at internal temperature of35±5° C., and the mixture was cooled to internal temperature of 15±5°C., and stirred at the same temperature for about 31 hr. The crystalswere collected by filtration, washed with ethanol (20 mL, cooled to15±5° C.), and dried at external temperature 50±10° C. under reducedpressure to give1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(9.04 g, yield 90.4%, HPLC area percent: 99.8%) as white crystals.

The HPLC measurement conditions in Example 15 and Example 16 is shown inthe following.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 230 nm)

column: Sunfire C18 S-3.5 μm, 4.6 mm i.d.×10 cm (manufactured by Waters)

mobile phase: (A) a mixed solvent of 0.05 mol/L phosphorate buffersolution (pH2.0)/acetonitrile (31:9 (volume ratio))

(B) a mixed solvent of 0.05 mol/L phosphorate buffer solution(pH2.0)/acetonitrile (12:13 (volume ratio))

gradient program (linear)

TABLE 6 Time (min) A solution (%) B solution (%) 0 (injection) 100 0 20100 0 55 0 100 55.1 100 0 65 100 0

flow rate: 1.0 mL/min.

measurement time: 60 min

analysis temperature: 40° C.

retention time:6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(7.7 min),1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(14.5 min)

Reference Example 5 (Production of a Seed Crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea)

Dimethylsulfoxide (25 mL) and1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(10.00 g) were charged into a reactor, and the mixture was dissolved bywarming to internal temperature of 35±5° C. After confirming thedissolution of the mixture, ethanol (35 mL) was added thereto atinternal temperature of 35±5° C., and the mixture was stirred atinternal temperature of 35±5° C. for 5 days. After confirming that theprecipitated crystals showed a powder X-ray diffraction patternidentical to that shown as in FIG. 2 , ethanol (140 mL) was addeddropwise thereto at internal temperature of 35±5° C., and the mixturewas cooled to internal temperature of 25±5° C., and stirred at the sametemperature for 3 days. The crystals were collected by filtration,washed with ethanol (20 mL, cooled to 25±5° C.), and dried at externaltemperature 50±10° C. under reduced pressure to give a seed crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(8.24 g, yield 82.4%) as white crystals.

<HPLC Condition>

detector: ultraviolet absorptiometer (measurement wavelength 230 nm)

column: Sunfire C18 S-3.5 μm, 4.6 mm i.d.×10 cm (manufactured by Waters)

mobile phase: (A) a mixed solvent of 0.05 mol/L phosphorate buffersolution (pH2.0)/acetonitrile (31:9 (volume ratio))

(B) a mixed solvent of 0.05 mol/L phosphorate buffer solution(pH2.0)/acetonitrile (12:13 (volume ratio))

gradient program (linear)

TABLE 7 Time (min) A solution (%) B solution (%) 0 (injection) 100 0 20100 0 55 0 100 55.1 100 0 65 100 0

flow rate: 1.0 mL/min.

measurement time: 60 min

analysis temperature: 40° C.

retention time:6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione(7.7 min),1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea(14.5 min)

INDUSTRIAL APPLICABILITY

According to the present invention,1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with high quality can be more safely produced in highyield. In addition, a crystal of1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof with high quality can be easily and efficientlyproduced.

Compounds (I) and (II) are useful as raw material compounds forproducing1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyureaor a salt thereof.

This application is based on patent application No. 217679/2012 filed inJapan, the contents of which are hereby incorporated by reference.

1-9. (canceled) 10: A compound represented by the formula (I).

or a salt thereof, wherein R1 is a C1-6 alkoxy group. 11: The compoundof claim 10 or salt thereof, wherein R1 is a methoxy group. 12: Thecompound of claim 10 or salt thereof, wherein R1 is an ethoxy group. 13:The compound of claim 10 or salt thereof, wherein R1 is a C3 alkoxygroup. 14: The compound of claim 10 or salt thereof, wherein R1 is a C4alkoxy group. 15: The compound of claim 10 or salt thereof, wherein R1is a C5 alkoxy group. 16: The compound of claim 10 or salt thereof,wherein R1 is a C6 alkoxy group. 17: A method of producing the compoundof claim 12, or a salt thereof, which comprises reacting ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylate,or a salt thereof, with N-bromosuccinimide and a radical initiator, andreacting the obtained ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylate,or salt thereof, with dimethylamine or a salt thereof. 18: The method ofclaim 17, wherein the N-bromosuccinimide is used in an amount in therange of 1.0 to 1.5 molar equivalents per molar equivalent of the ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof. 19: The method of claim 17, wherein the reaction ofethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof with N-bromosuccinimide and the radical initiator isperformed in the presence of trifluoromethylbenzene. 20: The method ofclaim 19, wherein the trifluoromethylbenzene is used in an amount in therange of 0.1 mL to 1.0 mL per 1 mmol of the ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof. 21: The method of claim 17, wherein the radicalinitiator is 2,2′-azobis(2,4-dimethylvaleronitrile). 22: The method ofclaim 21, wherein the 2,2′-azobis(2,4-dimethylvaleronitrile) is used inan amount in the range of 0.01 to 0.2 molar equivalents per molarequivalent of the ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof. 23: The method of claim 17, wherein the radicalinitiator is 2,2′-azobisisobutyronitrile. 24: The method of claim 17,wherein the reaction of ethyl2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-4-methyl-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof with N-bromosuccinimide and the radical initiator isperformed in a solvent. 25: The method of claim 24, wherein the solventcomprises ethyl acetate, carbon tetrachloride, dichloromethane,dichloroethane, chlorobenzene, or acetonitrile. 26: The method of claim17, wherein the dimethylamine is used in an amount in the range of 1.0to 3.0 molar equivalents per molar equivalent of the ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof. 27: The method of claim 17, wherein the dimethylamineis used in an amount in the range of 1.2 to 1.8 molar equivalents permolar equivalent of the ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof. 28: The method of claim 17, wherein the reaction of theethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof with dimethylamine or salt thereof is performed in thepresence of a solvent. 29: The method of claim 28, wherein the solventcomprises dimethylformamide, dimethylacetamide, or tetrahydrofuran. 30:The method of claim 17, wherein the reaction of the ethyl4-bromomethyl-2-[(2,6-difluorobenzyl)ethoxycarbonylamino]-5-(4-nitrophenyl)thiophene-3-carboxylateor salt thereof with dimethylamine or salt thereof is performed in thepresence of a base. 31: The method of claim 30, wherein the base istriethylamine or diisopropylethylamine.